A person entering an armed situation has many things about which to worry. Of paramount concern is the presence, capability, and actions of an opponent as well as the person's own security and risk. All other concerns are secondary and, too often are distractions from the primary objective.
Lights and laser sights are common equipment used with firearms in tactical situations. When these devices are used with a handgun, they are usually mounted underneath the barrel as this location is least obstructive to a user's line of sight and also easily concealed in a holster without the need to remove the unit. However, locating a sighting or lighting device in this particular area of a handgun makes it inherently cumbersome to activate or deactivate. Historically these lights or laser sights have been activated by a button. However, this button can be accidentally activated by a holster, be hard to reach, and activating the device requires the extra step of pressing the button which introduces a potentially dangerous distraction in an armed situation.
Automatic switches have been developed for these devices, but these automatic switches have limitations. One version of the automatic switch requires specially equipped holsters that will activate the switch when drawing the gun. If the user does not have the required special equipment on their holster, the automatic switching feature does not work. Other types of automatic switches rely on locating a button on the grip of the gun to activate the device. However, this type of switch makes it difficult to keep a sure grip on the gun. Furthermore, these types of automatic switches tend to be unreliable. For automatic switches requiring specially equipped holsters, if the holsters do not properly switch the device when holstered, then the device will stay on in the holster which prematurely drains the battery. For devices with buttons on the grip, if the user is not able properly grab the grip with the button, then the button switch will not activate.
Motion switches exist which can automatically activate or deactivate devices by sensing inertial motion. Common applications include inertial switches that dis-engage a laptop computer's hard drive if the computer is dropped, as well as inertial switches that deploy an airbag in the case of a motor vehicle collision. However, these types of switches, once they are activated, are typically used to permanently change the state of the device to which they are associated. One problem with using an inertial switch to both activate and deactivate a device is the rebound effect. When an inertial switch first registers an acceleration that is above the threshold necessary to activate the switch, the rebound of the motion sensing apparatus may register an acceleration in the opposite direction large enough to cross an opposite threshold that deactivates the switch. An example of this might be trying to sense the inertial upward motion inherent in drawing a weapon vertically from a holstered position. The upward motion of the draw may register a large enough acceleration in a motion sensor to activate a laser attached to the weapon. However, as the motion sensor rebounds, the acceleration of the rebound may be large enough to cross an opposite lower bounded threshold that deactivates the laser.
Furthermore, activation or deactivation of devices by inertial switches can be complicated by motion sensors being unable to distinguish between unintended activation signals versus intended activation signals. In the example of the weapon drawn from a holster, an inertial motion sensor may not be able to distinguish the difference between a weapon being drawn vertically from a holster and a holstered weapon on a user who is rapidly ascending a set of stairs. These two activities can cause the motion sensor to register similar values, and both activities could activate the laser, but in the case of drawing the weapon, the user intends to activate the laser, but in the case of rapidly ascending a set of stairs with the gun holstered, the user does not intend to activate the laser.
The present invention is a motion activated switch for an associated electronic device and methodology for activating that switch. The switch is useful for a firearm laser sight, but may be adapted to other uses. The switch utilizes algorithms which decrease unintended activation and deactivation of the switch and the associated device.
The present invention represents a departure from the prior art in that the switch of the present invention allows for more precise motion control of an electronic device.